--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/http2.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,2438 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#ifdef USE_NGHTTP2
+#include <nghttp2/nghttp2.h>
+#include "urldata.h"
+#include "http2.h"
+#include "http.h"
+#include "sendf.h"
+#include "select.h"
+#include "curl_base64.h"
+#include "strcase.h"
+#include "multiif.h"
+#include "url.h"
+#include "connect.h"
+#include "strtoofft.h"
+#include "strdup.h"
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "memdebug.h"
+
+#define H2_BUFSIZE 32768
+
+#if (NGHTTP2_VERSION_NUM < 0x010000)
+#error too old nghttp2 version, upgrade!
+#endif
+
+#if (NGHTTP2_VERSION_NUM > 0x010800)
+#define NGHTTP2_HAS_HTTP2_STRERROR 1
+#endif
+
+#if (NGHTTP2_VERSION_NUM >= 0x010900)
+/* nghttp2_session_callbacks_set_error_callback is present in nghttp2 1.9.0 or
+   later */
+#define NGHTTP2_HAS_ERROR_CALLBACK 1
+#else
+#define nghttp2_session_callbacks_set_error_callback(x,y)
+#endif
+
+#if (NGHTTP2_VERSION_NUM >= 0x010c00)
+#define NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE 1
+#endif
+
+#define HTTP2_HUGE_WINDOW_SIZE (1 << 30)
+
+#ifdef DEBUG_HTTP2
+#define H2BUGF(x) x
+#else
+#define H2BUGF(x) do { } WHILE_FALSE
+#endif
+
+
+static ssize_t http2_recv(struct connectdata *conn, int sockindex,
+                          char *mem, size_t len, CURLcode *err);
+static bool http2_connisdead(struct connectdata *conn);
+static int h2_session_send(struct Curl_easy *data,
+                           nghttp2_session *h2);
+static int h2_process_pending_input(struct connectdata *conn,
+                                    struct http_conn *httpc,
+                                    CURLcode *err);
+
+/*
+ * Curl_http2_init_state() is called when the easy handle is created and
+ * allows for HTTP/2 specific init of state.
+ */
+void Curl_http2_init_state(struct UrlState *state)
+{
+  state->stream_weight = NGHTTP2_DEFAULT_WEIGHT;
+}
+
+/*
+ * Curl_http2_init_userset() is called when the easy handle is created and
+ * allows for HTTP/2 specific user-set fields.
+ */
+void Curl_http2_init_userset(struct UserDefined *set)
+{
+  set->stream_weight = NGHTTP2_DEFAULT_WEIGHT;
+}
+
+static int http2_perform_getsock(const struct connectdata *conn,
+                                 curl_socket_t *sock)
+{
+  const struct http_conn *c = &conn->proto.httpc;
+  struct SingleRequest *k = &conn->data->req;
+  int bitmap = GETSOCK_BLANK;
+
+  sock[0] = conn->sock[FIRSTSOCKET];
+
+  /* in a HTTP/2 connection we can basically always get a frame so we should
+     always be ready for one */
+  bitmap |= GETSOCK_READSOCK(FIRSTSOCKET);
+
+  /* we're still uploading or the HTTP/2 layer wants to send data */
+  if(((k->keepon & (KEEP_SEND|KEEP_SEND_PAUSE)) == KEEP_SEND) ||
+     nghttp2_session_want_write(c->h2))
+    bitmap |= GETSOCK_WRITESOCK(FIRSTSOCKET);
+
+  return bitmap;
+}
+
+static int http2_getsock(struct connectdata *conn,
+                         curl_socket_t *socks)
+{
+  return http2_perform_getsock(conn, socks);
+}
+
+/*
+ * http2_stream_free() free HTTP2 stream related data
+ */
+static void http2_stream_free(struct HTTP *http)
+{
+  if(http) {
+    Curl_add_buffer_free(&http->header_recvbuf);
+    Curl_add_buffer_free(&http->trailer_recvbuf);
+    for(; http->push_headers_used > 0; --http->push_headers_used) {
+      free(http->push_headers[http->push_headers_used - 1]);
+    }
+    free(http->push_headers);
+    http->push_headers = NULL;
+  }
+}
+
+/*
+ * Disconnects *a* connection used for HTTP/2. It might be an old one from the
+ * connection cache and not the "main" one. Don't touch the easy handle!
+ */
+
+static CURLcode http2_disconnect(struct connectdata *conn,
+                                 bool dead_connection)
+{
+  struct http_conn *c = &conn->proto.httpc;
+  (void)dead_connection;
+
+  H2BUGF(infof(conn->data, "HTTP/2 DISCONNECT starts now\n"));
+
+  nghttp2_session_del(c->h2);
+  Curl_safefree(c->inbuf);
+
+  H2BUGF(infof(conn->data, "HTTP/2 DISCONNECT done\n"));
+
+  return CURLE_OK;
+}
+
+/*
+ * The server may send us data at any point (e.g. PING frames). Therefore,
+ * we cannot assume that an HTTP/2 socket is dead just because it is readable.
+ *
+ * Instead, if it is readable, run Curl_connalive() to peek at the socket
+ * and distinguish between closed and data.
+ */
+static bool http2_connisdead(struct connectdata *conn)
+{
+  int sval;
+  bool dead = TRUE;
+
+  if(conn->bits.close)
+    return TRUE;
+
+  sval = SOCKET_READABLE(conn->sock[FIRSTSOCKET], 0);
+  if(sval == 0) {
+    /* timeout */
+    dead = FALSE;
+  }
+  else if(sval & CURL_CSELECT_ERR) {
+    /* socket is in an error state */
+    dead = TRUE;
+  }
+  else if(sval & CURL_CSELECT_IN) {
+    /* readable with no error. could still be closed */
+    dead = !Curl_connalive(conn);
+    if(!dead) {
+      /* This happens before we've sent off a request and the connection is
+         not in use by any other transfer, there shouldn't be any data here,
+         only "protocol frames" */
+      CURLcode result;
+      struct http_conn *httpc = &conn->proto.httpc;
+      ssize_t nread = -1;
+      if(httpc->recv_underlying)
+        /* if called "too early", this pointer isn't setup yet! */
+        nread = ((Curl_recv *)httpc->recv_underlying)(
+          conn, FIRSTSOCKET, httpc->inbuf, H2_BUFSIZE, &result);
+      if(nread != -1) {
+        infof(conn->data,
+              "%d bytes stray data read before trying h2 connection\n",
+              (int)nread);
+        httpc->nread_inbuf = 0;
+        httpc->inbuflen = nread;
+        (void)h2_process_pending_input(conn, httpc, &result);
+      }
+      else
+        /* the read failed so let's say this is dead anyway */
+        dead = TRUE;
+    }
+  }
+
+  return dead;
+}
+
+static unsigned int http2_conncheck(struct connectdata *check,
+                                    unsigned int checks_to_perform)
+{
+  unsigned int ret_val = CONNRESULT_NONE;
+  struct http_conn *c = &check->proto.httpc;
+  int rc;
+  bool send_frames = false;
+
+  if(checks_to_perform & CONNCHECK_ISDEAD) {
+    if(http2_connisdead(check))
+      ret_val |= CONNRESULT_DEAD;
+  }
+
+  if(checks_to_perform & CONNCHECK_KEEPALIVE) {
+    struct curltime now = Curl_now();
+    timediff_t elapsed = Curl_timediff(now, check->keepalive);
+
+    if(elapsed > check->upkeep_interval_ms) {
+      /* Perform an HTTP/2 PING */
+      rc = nghttp2_submit_ping(c->h2, 0, ZERO_NULL);
+      if(!rc) {
+        /* Successfully added a PING frame to the session. Need to flag this
+           so the frame is sent. */
+        send_frames = true;
+      }
+      else {
+       failf(check->data, "nghttp2_submit_ping() failed: %s(%d)",
+             nghttp2_strerror(rc), rc);
+      }
+
+      check->keepalive = now;
+    }
+  }
+
+  if(send_frames) {
+    rc = nghttp2_session_send(c->h2);
+    if(rc)
+      failf(check->data, "nghttp2_session_send() failed: %s(%d)",
+            nghttp2_strerror(rc), rc);
+  }
+
+  return ret_val;
+}
+
+/* called from http_setup_conn */
+void Curl_http2_setup_req(struct Curl_easy *data)
+{
+  struct HTTP *http = data->req.protop;
+
+  http->nread_header_recvbuf = 0;
+  http->bodystarted = FALSE;
+  http->status_code = -1;
+  http->pausedata = NULL;
+  http->pauselen = 0;
+  http->closed = FALSE;
+  http->close_handled = FALSE;
+  http->mem = data->state.buffer;
+  http->len = data->set.buffer_size;
+  http->memlen = 0;
+}
+
+/* called from http_setup_conn */
+void Curl_http2_setup_conn(struct connectdata *conn)
+{
+  conn->proto.httpc.settings.max_concurrent_streams =
+    DEFAULT_MAX_CONCURRENT_STREAMS;
+  conn->proto.httpc.error_code = NGHTTP2_NO_ERROR;
+}
+
+/*
+ * HTTP2 handler interface. This isn't added to the general list of protocols
+ * but will be used at run-time when the protocol is dynamically switched from
+ * HTTP to HTTP2.
+ */
+static const struct Curl_handler Curl_handler_http2 = {
+  "HTTP",                               /* scheme */
+  ZERO_NULL,                            /* setup_connection */
+  Curl_http,                            /* do_it */
+  Curl_http_done,                       /* done */
+  ZERO_NULL,                            /* do_more */
+  ZERO_NULL,                            /* connect_it */
+  ZERO_NULL,                            /* connecting */
+  ZERO_NULL,                            /* doing */
+  http2_getsock,                        /* proto_getsock */
+  http2_getsock,                        /* doing_getsock */
+  ZERO_NULL,                            /* domore_getsock */
+  http2_perform_getsock,                /* perform_getsock */
+  http2_disconnect,                     /* disconnect */
+  ZERO_NULL,                            /* readwrite */
+  http2_conncheck,                      /* connection_check */
+  PORT_HTTP,                            /* defport */
+  CURLPROTO_HTTP,                       /* protocol */
+  PROTOPT_STREAM                        /* flags */
+};
+
+static const struct Curl_handler Curl_handler_http2_ssl = {
+  "HTTPS",                              /* scheme */
+  ZERO_NULL,                            /* setup_connection */
+  Curl_http,                            /* do_it */
+  Curl_http_done,                       /* done */
+  ZERO_NULL,                            /* do_more */
+  ZERO_NULL,                            /* connect_it */
+  ZERO_NULL,                            /* connecting */
+  ZERO_NULL,                            /* doing */
+  http2_getsock,                        /* proto_getsock */
+  http2_getsock,                        /* doing_getsock */
+  ZERO_NULL,                            /* domore_getsock */
+  http2_perform_getsock,                /* perform_getsock */
+  http2_disconnect,                     /* disconnect */
+  ZERO_NULL,                            /* readwrite */
+  http2_conncheck,                      /* connection_check */
+  PORT_HTTP,                            /* defport */
+  CURLPROTO_HTTPS,                      /* protocol */
+  PROTOPT_SSL | PROTOPT_STREAM          /* flags */
+};
+
+/*
+ * Store nghttp2 version info in this buffer, Prefix with a space.  Return
+ * total length written.
+ */
+int Curl_http2_ver(char *p, size_t len)
+{
+  nghttp2_info *h2 = nghttp2_version(0);
+  return msnprintf(p, len, " nghttp2/%s", h2->version_str);
+}
+
+/* HTTP/2 error code to name based on the Error Code Registry.
+https://tools.ietf.org/html/rfc7540#page-77
+nghttp2_error_code enums are identical.
+*/
+static const char *http2_strerror(uint32_t err)
+{
+#ifndef NGHTTP2_HAS_HTTP2_STRERROR
+  const char *str[] = {
+    "NO_ERROR",             /* 0x0 */
+    "PROTOCOL_ERROR",       /* 0x1 */
+    "INTERNAL_ERROR",       /* 0x2 */
+    "FLOW_CONTROL_ERROR",   /* 0x3 */
+    "SETTINGS_TIMEOUT",     /* 0x4 */
+    "STREAM_CLOSED",        /* 0x5 */
+    "FRAME_SIZE_ERROR",     /* 0x6 */
+    "REFUSED_STREAM",       /* 0x7 */
+    "CANCEL",               /* 0x8 */
+    "COMPRESSION_ERROR",    /* 0x9 */
+    "CONNECT_ERROR",        /* 0xA */
+    "ENHANCE_YOUR_CALM",    /* 0xB */
+    "INADEQUATE_SECURITY",  /* 0xC */
+    "HTTP_1_1_REQUIRED"     /* 0xD */
+  };
+  return (err < sizeof(str) / sizeof(str[0])) ? str[err] : "unknown";
+#else
+  return nghttp2_http2_strerror(err);
+#endif
+}
+
+/*
+ * The implementation of nghttp2_send_callback type. Here we write |data| with
+ * size |length| to the network and return the number of bytes actually
+ * written. See the documentation of nghttp2_send_callback for the details.
+ */
+static ssize_t send_callback(nghttp2_session *h2,
+                             const uint8_t *data, size_t length, int flags,
+                             void *userp)
+{
+  struct connectdata *conn = (struct connectdata *)userp;
+  struct http_conn *c = &conn->proto.httpc;
+  ssize_t written;
+  CURLcode result = CURLE_OK;
+
+  (void)h2;
+  (void)flags;
+
+  if(!c->send_underlying)
+    /* called before setup properly! */
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+  written = ((Curl_send*)c->send_underlying)(conn, FIRSTSOCKET,
+                                             data, length, &result);
+
+  if(result == CURLE_AGAIN) {
+    return NGHTTP2_ERR_WOULDBLOCK;
+  }
+
+  if(written == -1) {
+    failf(conn->data, "Failed sending HTTP2 data");
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  }
+
+  if(!written)
+    return NGHTTP2_ERR_WOULDBLOCK;
+
+  return written;
+}
+
+
+/* We pass a pointer to this struct in the push callback, but the contents of
+   the struct are hidden from the user. */
+struct curl_pushheaders {
+  struct Curl_easy *data;
+  const nghttp2_push_promise *frame;
+};
+
+/*
+ * push header access function. Only to be used from within the push callback
+ */
+char *curl_pushheader_bynum(struct curl_pushheaders *h, size_t num)
+{
+  /* Verify that we got a good easy handle in the push header struct, mostly to
+     detect rubbish input fast(er). */
+  if(!h || !GOOD_EASY_HANDLE(h->data))
+    return NULL;
+  else {
+    struct HTTP *stream = h->data->req.protop;
+    if(num < stream->push_headers_used)
+      return stream->push_headers[num];
+  }
+  return NULL;
+}
+
+/*
+ * push header access function. Only to be used from within the push callback
+ */
+char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
+{
+  /* Verify that we got a good easy handle in the push header struct,
+     mostly to detect rubbish input fast(er). Also empty header name
+     is just a rubbish too. We have to allow ":" at the beginning of
+     the header, but header == ":" must be rejected. If we have ':' in
+     the middle of header, it could be matched in middle of the value,
+     this is because we do prefix match.*/
+  if(!h || !GOOD_EASY_HANDLE(h->data) || !header || !header[0] ||
+     !strcmp(header, ":") || strchr(header + 1, ':'))
+    return NULL;
+  else {
+    struct HTTP *stream = h->data->req.protop;
+    size_t len = strlen(header);
+    size_t i;
+    for(i = 0; i<stream->push_headers_used; i++) {
+      if(!strncmp(header, stream->push_headers[i], len)) {
+        /* sub-match, make sure that it is followed by a colon */
+        if(stream->push_headers[i][len] != ':')
+          continue;
+        return &stream->push_headers[i][len + 1];
+      }
+    }
+  }
+  return NULL;
+}
+
+/*
+ * This specific transfer on this connection has been "drained".
+ */
+static void drained_transfer(struct Curl_easy *data,
+                             struct http_conn *httpc)
+{
+  DEBUGASSERT(httpc->drain_total >= data->state.drain);
+  httpc->drain_total -= data->state.drain;
+  data->state.drain = 0;
+}
+
+/*
+ * Mark this transfer to get "drained".
+ */
+static void drain_this(struct Curl_easy *data,
+                       struct http_conn *httpc)
+{
+  data->state.drain++;
+  httpc->drain_total++;
+  DEBUGASSERT(httpc->drain_total >= data->state.drain);
+}
+
+static struct Curl_easy *duphandle(struct Curl_easy *data)
+{
+  struct Curl_easy *second = curl_easy_duphandle(data);
+  if(second) {
+    /* setup the request struct */
+    struct HTTP *http = calloc(1, sizeof(struct HTTP));
+    if(!http) {
+      (void)Curl_close(second);
+      second = NULL;
+    }
+    else {
+      second->req.protop = http;
+      http->header_recvbuf = Curl_add_buffer_init();
+      if(!http->header_recvbuf) {
+        free(http);
+        (void)Curl_close(second);
+        second = NULL;
+      }
+      else {
+        Curl_http2_setup_req(second);
+        second->state.stream_weight = data->state.stream_weight;
+      }
+    }
+  }
+  return second;
+}
+
+
+static int push_promise(struct Curl_easy *data,
+                        struct connectdata *conn,
+                        const nghttp2_push_promise *frame)
+{
+  int rv;
+  H2BUGF(infof(data, "PUSH_PROMISE received, stream %u!\n",
+               frame->promised_stream_id));
+  if(data->multi->push_cb) {
+    struct HTTP *stream;
+    struct HTTP *newstream;
+    struct curl_pushheaders heads;
+    CURLMcode rc;
+    struct http_conn *httpc;
+    size_t i;
+    /* clone the parent */
+    struct Curl_easy *newhandle = duphandle(data);
+    if(!newhandle) {
+      infof(data, "failed to duplicate handle\n");
+      rv = 1; /* FAIL HARD */
+      goto fail;
+    }
+
+    heads.data = data;
+    heads.frame = frame;
+    /* ask the application */
+    H2BUGF(infof(data, "Got PUSH_PROMISE, ask application!\n"));
+
+    stream = data->req.protop;
+    if(!stream) {
+      failf(data, "Internal NULL stream!\n");
+      (void)Curl_close(newhandle);
+      rv = 1;
+      goto fail;
+    }
+
+    Curl_set_in_callback(data, true);
+    rv = data->multi->push_cb(data, newhandle,
+                              stream->push_headers_used, &heads,
+                              data->multi->push_userp);
+    Curl_set_in_callback(data, false);
+
+    /* free the headers again */
+    for(i = 0; i<stream->push_headers_used; i++)
+      free(stream->push_headers[i]);
+    free(stream->push_headers);
+    stream->push_headers = NULL;
+    stream->push_headers_used = 0;
+
+    if(rv) {
+      /* denied, kill off the new handle again */
+      http2_stream_free(newhandle->req.protop);
+      newhandle->req.protop = NULL;
+      (void)Curl_close(newhandle);
+      goto fail;
+    }
+
+    newstream = newhandle->req.protop;
+    newstream->stream_id = frame->promised_stream_id;
+    newhandle->req.maxdownload = -1;
+    newhandle->req.size = -1;
+
+    /* approved, add to the multi handle and immediately switch to PERFORM
+       state with the given connection !*/
+    rc = Curl_multi_add_perform(data->multi, newhandle, conn);
+    if(rc) {
+      infof(data, "failed to add handle to multi\n");
+      http2_stream_free(newhandle->req.protop);
+      newhandle->req.protop = NULL;
+      Curl_close(newhandle);
+      rv = 1;
+      goto fail;
+    }
+
+    httpc = &conn->proto.httpc;
+    rv = nghttp2_session_set_stream_user_data(httpc->h2,
+                                              frame->promised_stream_id,
+                                              newhandle);
+    if(rv) {
+      infof(data, "failed to set user_data for stream %d\n",
+            frame->promised_stream_id);
+      DEBUGASSERT(0);
+      goto fail;
+    }
+  }
+  else {
+    H2BUGF(infof(data, "Got PUSH_PROMISE, ignore it!\n"));
+    rv = 1;
+  }
+  fail:
+  return rv;
+}
+
+/*
+ * multi_connchanged() is called to tell that there is a connection in
+ * this multi handle that has changed state (multiplexing become possible, the
+ * number of allowed streams changed or similar), and a subsequent use of this
+ * multi handle should move CONNECT_PEND handles back to CONNECT to have them
+ * retry.
+ */
+static void multi_connchanged(struct Curl_multi *multi)
+{
+  multi->recheckstate = TRUE;
+}
+
+static int on_frame_recv(nghttp2_session *session, const nghttp2_frame *frame,
+                         void *userp)
+{
+  struct connectdata *conn = (struct connectdata *)userp;
+  struct http_conn *httpc = &conn->proto.httpc;
+  struct Curl_easy *data_s = NULL;
+  struct HTTP *stream = NULL;
+  int rv;
+  size_t left, ncopy;
+  int32_t stream_id = frame->hd.stream_id;
+  CURLcode result;
+
+  if(!stream_id) {
+    /* stream ID zero is for connection-oriented stuff */
+    if(frame->hd.type == NGHTTP2_SETTINGS) {
+      uint32_t max_conn = httpc->settings.max_concurrent_streams;
+      H2BUGF(infof(conn->data, "Got SETTINGS\n"));
+      httpc->settings.max_concurrent_streams =
+        nghttp2_session_get_remote_settings(
+          session, NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS);
+      httpc->settings.enable_push =
+        nghttp2_session_get_remote_settings(
+          session, NGHTTP2_SETTINGS_ENABLE_PUSH);
+      H2BUGF(infof(conn->data, "MAX_CONCURRENT_STREAMS == %d\n",
+                   httpc->settings.max_concurrent_streams));
+      H2BUGF(infof(conn->data, "ENABLE_PUSH == %s\n",
+                   httpc->settings.enable_push?"TRUE":"false"));
+      if(max_conn != httpc->settings.max_concurrent_streams) {
+        /* only signal change if the value actually changed */
+        infof(conn->data,
+              "Connection state changed (MAX_CONCURRENT_STREAMS == %u)!\n",
+              httpc->settings.max_concurrent_streams);
+        multi_connchanged(conn->data->multi);
+      }
+    }
+    return 0;
+  }
+  data_s = nghttp2_session_get_stream_user_data(session, stream_id);
+  if(!data_s) {
+    H2BUGF(infof(conn->data,
+                 "No Curl_easy associated with stream: %x\n",
+                 stream_id));
+    return 0;
+  }
+
+  stream = data_s->req.protop;
+  if(!stream) {
+    H2BUGF(infof(data_s, "No proto pointer for stream: %x\n",
+                 stream_id));
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  }
+
+  H2BUGF(infof(data_s, "on_frame_recv() header %x stream %x\n",
+               frame->hd.type, stream_id));
+
+  switch(frame->hd.type) {
+  case NGHTTP2_DATA:
+    /* If body started on this stream, then receiving DATA is illegal. */
+    if(!stream->bodystarted) {
+      rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
+                                     stream_id, NGHTTP2_PROTOCOL_ERROR);
+
+      if(nghttp2_is_fatal(rv)) {
+        return NGHTTP2_ERR_CALLBACK_FAILURE;
+      }
+    }
+    break;
+  case NGHTTP2_HEADERS:
+    if(stream->bodystarted) {
+      /* Only valid HEADERS after body started is trailer HEADERS.  We
+         buffer them in on_header callback. */
+      break;
+    }
+
+    /* nghttp2 guarantees that :status is received, and we store it to
+       stream->status_code. Fuzzing has proven this can still be reached
+       without status code having been set. */
+    if(stream->status_code == -1)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+    /* Only final status code signals the end of header */
+    if(stream->status_code / 100 != 1) {
+      stream->bodystarted = TRUE;
+      stream->status_code = -1;
+    }
+
+    result = Curl_add_buffer(&stream->header_recvbuf, "\r\n", 2);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+    left = stream->header_recvbuf->size_used - stream->nread_header_recvbuf;
+    ncopy = CURLMIN(stream->len, left);
+
+    memcpy(&stream->mem[stream->memlen],
+           stream->header_recvbuf->buffer + stream->nread_header_recvbuf,
+           ncopy);
+    stream->nread_header_recvbuf += ncopy;
+
+    H2BUGF(infof(data_s, "Store %zu bytes headers from stream %u at %p\n",
+                 ncopy, stream_id, stream->mem));
+
+    stream->len -= ncopy;
+    stream->memlen += ncopy;
+
+    drain_this(data_s, httpc);
+    {
+      /* get the pointer from userp again since it was re-assigned above */
+      struct connectdata *conn_s = (struct connectdata *)userp;
+
+      /* if we receive data for another handle, wake that up */
+      if(conn_s->data != data_s)
+        Curl_expire(data_s, 0, EXPIRE_RUN_NOW);
+    }
+    break;
+  case NGHTTP2_PUSH_PROMISE:
+    rv = push_promise(data_s, conn, &frame->push_promise);
+    if(rv) { /* deny! */
+      rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
+                                     frame->push_promise.promised_stream_id,
+                                     NGHTTP2_CANCEL);
+      if(nghttp2_is_fatal(rv)) {
+        return rv;
+      }
+    }
+    break;
+  default:
+    H2BUGF(infof(data_s, "Got frame type %x for stream %u!\n",
+                 frame->hd.type, stream_id));
+    break;
+  }
+  return 0;
+}
+
+static int on_data_chunk_recv(nghttp2_session *session, uint8_t flags,
+                              int32_t stream_id,
+                              const uint8_t *data, size_t len, void *userp)
+{
+  struct HTTP *stream;
+  struct Curl_easy *data_s;
+  size_t nread;
+  struct connectdata *conn = (struct connectdata *)userp;
+  (void)session;
+  (void)flags;
+  (void)data;
+
+  DEBUGASSERT(stream_id); /* should never be a zero stream ID here */
+
+  /* get the stream from the hash based on Stream ID */
+  data_s = nghttp2_session_get_stream_user_data(session, stream_id);
+  if(!data_s)
+    /* Receiving a Stream ID not in the hash should not happen, this is an
+       internal error more than anything else! */
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+  stream = data_s->req.protop;
+  if(!stream)
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+  nread = CURLMIN(stream->len, len);
+  memcpy(&stream->mem[stream->memlen], data, nread);
+
+  stream->len -= nread;
+  stream->memlen += nread;
+
+  drain_this(data_s, &conn->proto.httpc);
+
+  /* if we receive data for another handle, wake that up */
+  if(conn->data != data_s)
+    Curl_expire(data_s, 0, EXPIRE_RUN_NOW);
+
+  H2BUGF(infof(data_s, "%zu data received for stream %u "
+               "(%zu left in buffer %p, total %zu)\n",
+               nread, stream_id,
+               stream->len, stream->mem,
+               stream->memlen));
+
+  if(nread < len) {
+    stream->pausedata = data + nread;
+    stream->pauselen = len - nread;
+    H2BUGF(infof(data_s, "NGHTTP2_ERR_PAUSE - %zu bytes out of buffer"
+                 ", stream %u\n",
+                 len - nread, stream_id));
+    data_s->conn->proto.httpc.pause_stream_id = stream_id;
+
+    return NGHTTP2_ERR_PAUSE;
+  }
+
+  /* pause execution of nghttp2 if we received data for another handle
+     in order to process them first. */
+  if(conn->data != data_s) {
+    data_s->conn->proto.httpc.pause_stream_id = stream_id;
+
+    return NGHTTP2_ERR_PAUSE;
+  }
+
+  return 0;
+}
+
+static int on_stream_close(nghttp2_session *session, int32_t stream_id,
+                           uint32_t error_code, void *userp)
+{
+  struct Curl_easy *data_s;
+  struct HTTP *stream;
+  struct connectdata *conn = (struct connectdata *)userp;
+  int rv;
+  (void)session;
+  (void)stream_id;
+
+  if(stream_id) {
+    struct http_conn *httpc;
+    /* get the stream from the hash based on Stream ID, stream ID zero is for
+       connection-oriented stuff */
+    data_s = nghttp2_session_get_stream_user_data(session, stream_id);
+    if(!data_s) {
+      /* We could get stream ID not in the hash.  For example, if we
+         decided to reject stream (e.g., PUSH_PROMISE). */
+      return 0;
+    }
+    H2BUGF(infof(data_s, "on_stream_close(), %s (err %d), stream %u\n",
+                 http2_strerror(error_code), error_code, stream_id));
+    stream = data_s->req.protop;
+    if(!stream)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+    stream->closed = TRUE;
+    httpc = &conn->proto.httpc;
+    drain_this(data_s, httpc);
+    httpc->error_code = error_code;
+
+    /* remove the entry from the hash as the stream is now gone */
+    rv = nghttp2_session_set_stream_user_data(session, stream_id, 0);
+    if(rv) {
+      infof(data_s, "http/2: failed to clear user_data for stream %d!\n",
+            stream_id);
+      DEBUGASSERT(0);
+    }
+    if(stream_id == httpc->pause_stream_id) {
+      H2BUGF(infof(data_s, "Stopped the pause stream!\n"));
+      httpc->pause_stream_id = 0;
+    }
+    H2BUGF(infof(data_s, "Removed stream %u hash!\n", stream_id));
+    stream->stream_id = 0; /* cleared */
+  }
+  return 0;
+}
+
+static int on_begin_headers(nghttp2_session *session,
+                            const nghttp2_frame *frame, void *userp)
+{
+  struct HTTP *stream;
+  struct Curl_easy *data_s = NULL;
+  (void)userp;
+
+  data_s = nghttp2_session_get_stream_user_data(session, frame->hd.stream_id);
+  if(!data_s) {
+    return 0;
+  }
+
+  H2BUGF(infof(data_s, "on_begin_headers() was called\n"));
+
+  if(frame->hd.type != NGHTTP2_HEADERS) {
+    return 0;
+  }
+
+  stream = data_s->req.protop;
+  if(!stream || !stream->bodystarted) {
+    return 0;
+  }
+
+  if(!stream->trailer_recvbuf) {
+    stream->trailer_recvbuf = Curl_add_buffer_init();
+    if(!stream->trailer_recvbuf) {
+      return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
+    }
+  }
+  return 0;
+}
+
+/* Decode HTTP status code.  Returns -1 if no valid status code was
+   decoded. */
+static int decode_status_code(const uint8_t *value, size_t len)
+{
+  int i;
+  int res;
+
+  if(len != 3) {
+    return -1;
+  }
+
+  res = 0;
+
+  for(i = 0; i < 3; ++i) {
+    char c = value[i];
+
+    if(c < '0' || c > '9') {
+      return -1;
+    }
+
+    res *= 10;
+    res += c - '0';
+  }
+
+  return res;
+}
+
+/* frame->hd.type is either NGHTTP2_HEADERS or NGHTTP2_PUSH_PROMISE */
+static int on_header(nghttp2_session *session, const nghttp2_frame *frame,
+                     const uint8_t *name, size_t namelen,
+                     const uint8_t *value, size_t valuelen,
+                     uint8_t flags,
+                     void *userp)
+{
+  struct HTTP *stream;
+  struct Curl_easy *data_s;
+  int32_t stream_id = frame->hd.stream_id;
+  struct connectdata *conn = (struct connectdata *)userp;
+  CURLcode result;
+  (void)flags;
+
+  DEBUGASSERT(stream_id); /* should never be a zero stream ID here */
+
+  /* get the stream from the hash based on Stream ID */
+  data_s = nghttp2_session_get_stream_user_data(session, stream_id);
+  if(!data_s)
+    /* Receiving a Stream ID not in the hash should not happen, this is an
+       internal error more than anything else! */
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+  stream = data_s->req.protop;
+  if(!stream) {
+    failf(data_s, "Internal NULL stream! 5\n");
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  }
+
+  /* Store received PUSH_PROMISE headers to be used when the subsequent
+     PUSH_PROMISE callback comes */
+  if(frame->hd.type == NGHTTP2_PUSH_PROMISE) {
+    char *h;
+
+    if(!strcmp(":authority", (const char *)name)) {
+      /* pseudo headers are lower case */
+      int rc = 0;
+      char *check = aprintf("%s:%d", conn->host.name, conn->remote_port);
+      if(!check)
+        /* no memory */
+        return NGHTTP2_ERR_CALLBACK_FAILURE;
+      if(!Curl_strcasecompare(check, (const char *)value)) {
+        /* This is push is not for the same authority that was asked for in
+         * the URL. RFC 7540 section 8.2 says: "A client MUST treat a
+         * PUSH_PROMISE for which the server is not authoritative as a stream
+         * error of type PROTOCOL_ERROR."
+         */
+        (void)nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
+                                        stream_id, NGHTTP2_PROTOCOL_ERROR);
+        rc = NGHTTP2_ERR_CALLBACK_FAILURE;
+      }
+      free(check);
+      if(rc)
+        return rc;
+    }
+
+    if(!stream->push_headers) {
+      stream->push_headers_alloc = 10;
+      stream->push_headers = malloc(stream->push_headers_alloc *
+                                    sizeof(char *));
+      if(!stream->push_headers)
+        return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
+      stream->push_headers_used = 0;
+    }
+    else if(stream->push_headers_used ==
+            stream->push_headers_alloc) {
+      char **headp;
+      stream->push_headers_alloc *= 2;
+      headp = Curl_saferealloc(stream->push_headers,
+                               stream->push_headers_alloc * sizeof(char *));
+      if(!headp) {
+        stream->push_headers = NULL;
+        return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
+      }
+      stream->push_headers = headp;
+    }
+    h = aprintf("%s:%s", name, value);
+    if(h)
+      stream->push_headers[stream->push_headers_used++] = h;
+    return 0;
+  }
+
+  if(stream->bodystarted) {
+    /* This is trailer fields. */
+    /* 4 is for ": " and "\r\n". */
+    uint32_t n = (uint32_t)(namelen + valuelen + 4);
+
+    H2BUGF(infof(data_s, "h2 trailer: %.*s: %.*s\n", namelen, name, valuelen,
+                 value));
+
+    result = Curl_add_buffer(&stream->trailer_recvbuf, &n, sizeof(n));
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    result = Curl_add_buffer(&stream->trailer_recvbuf, name, namelen);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    result = Curl_add_buffer(&stream->trailer_recvbuf, ": ", 2);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    result = Curl_add_buffer(&stream->trailer_recvbuf, value, valuelen);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    result = Curl_add_buffer(&stream->trailer_recvbuf, "\r\n\0", 3);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+    return 0;
+  }
+
+  if(namelen == sizeof(":status") - 1 &&
+     memcmp(":status", name, namelen) == 0) {
+    /* nghttp2 guarantees :status is received first and only once, and
+       value is 3 digits status code, and decode_status_code always
+       succeeds. */
+    stream->status_code = decode_status_code(value, valuelen);
+    DEBUGASSERT(stream->status_code != -1);
+
+    result = Curl_add_buffer(&stream->header_recvbuf, "HTTP/2 ", 7);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    result = Curl_add_buffer(&stream->header_recvbuf, value, valuelen);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    /* the space character after the status code is mandatory */
+    result = Curl_add_buffer(&stream->header_recvbuf, " \r\n", 3);
+    if(result)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    /* if we receive data for another handle, wake that up */
+    if(conn->data != data_s)
+      Curl_expire(data_s, 0, EXPIRE_RUN_NOW);
+
+    H2BUGF(infof(data_s, "h2 status: HTTP/2 %03d (easy %p)\n",
+                 stream->status_code, data_s));
+    return 0;
+  }
+
+  /* nghttp2 guarantees that namelen > 0, and :status was already
+     received, and this is not pseudo-header field . */
+  /* convert to a HTTP1-style header */
+  result = Curl_add_buffer(&stream->header_recvbuf, name, namelen);
+  if(result)
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  result = Curl_add_buffer(&stream->header_recvbuf, ": ", 2);
+  if(result)
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  result = Curl_add_buffer(&stream->header_recvbuf, value, valuelen);
+  if(result)
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  result = Curl_add_buffer(&stream->header_recvbuf, "\r\n", 2);
+  if(result)
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  /* if we receive data for another handle, wake that up */
+  if(conn->data != data_s)
+    Curl_expire(data_s, 0, EXPIRE_RUN_NOW);
+
+  H2BUGF(infof(data_s, "h2 header: %.*s: %.*s\n", namelen, name, valuelen,
+               value));
+
+  return 0; /* 0 is successful */
+}
+
+static ssize_t data_source_read_callback(nghttp2_session *session,
+                                         int32_t stream_id,
+                                         uint8_t *buf, size_t length,
+                                         uint32_t *data_flags,
+                                         nghttp2_data_source *source,
+                                         void *userp)
+{
+  struct Curl_easy *data_s;
+  struct HTTP *stream = NULL;
+  size_t nread;
+  (void)source;
+  (void)userp;
+
+  if(stream_id) {
+    /* get the stream from the hash based on Stream ID, stream ID zero is for
+       connection-oriented stuff */
+    data_s = nghttp2_session_get_stream_user_data(session, stream_id);
+    if(!data_s)
+      /* Receiving a Stream ID not in the hash should not happen, this is an
+         internal error more than anything else! */
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+
+    stream = data_s->req.protop;
+    if(!stream)
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+  }
+  else
+    return NGHTTP2_ERR_INVALID_ARGUMENT;
+
+  nread = CURLMIN(stream->upload_len, length);
+  if(nread > 0) {
+    memcpy(buf, stream->upload_mem, nread);
+    stream->upload_mem += nread;
+    stream->upload_len -= nread;
+    if(data_s->state.infilesize != -1)
+      stream->upload_left -= nread;
+  }
+
+  if(stream->upload_left == 0)
+    *data_flags = NGHTTP2_DATA_FLAG_EOF;
+  else if(nread == 0)
+    return NGHTTP2_ERR_DEFERRED;
+
+  H2BUGF(infof(data_s, "data_source_read_callback: "
+               "returns %zu bytes stream %u\n",
+               nread, stream_id));
+
+  return nread;
+}
+
+#if defined(NGHTTP2_HAS_ERROR_CALLBACK) &&      \
+  !defined(CURL_DISABLE_VERBOSE_STRINGS)
+static int error_callback(nghttp2_session *session,
+                          const char *msg,
+                          size_t len,
+                          void *userp)
+{
+  struct connectdata *conn = (struct connectdata *)userp;
+  (void)session;
+  infof(conn->data, "http2 error: %.*s\n", len, msg);
+  return 0;
+}
+#endif
+
+static void populate_settings(struct connectdata *conn,
+                              struct http_conn *httpc)
+{
+  nghttp2_settings_entry *iv = httpc->local_settings;
+
+  iv[0].settings_id = NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS;
+  iv[0].value = 100;
+
+  iv[1].settings_id = NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE;
+  iv[1].value = HTTP2_HUGE_WINDOW_SIZE;
+
+  iv[2].settings_id = NGHTTP2_SETTINGS_ENABLE_PUSH;
+  iv[2].value = conn->data->multi->push_cb != NULL;
+
+  httpc->local_settings_num = 3;
+}
+
+void Curl_http2_done(struct connectdata *conn, bool premature)
+{
+  struct Curl_easy *data = conn->data;
+  struct HTTP *http = data->req.protop;
+  struct http_conn *httpc = &conn->proto.httpc;
+
+  /* there might be allocated resources done before this got the 'h2' pointer
+     setup */
+  if(http->header_recvbuf) {
+    Curl_add_buffer_free(&http->header_recvbuf);
+    Curl_add_buffer_free(&http->trailer_recvbuf);
+    if(http->push_headers) {
+      /* if they weren't used and then freed before */
+      for(; http->push_headers_used > 0; --http->push_headers_used) {
+        free(http->push_headers[http->push_headers_used - 1]);
+      }
+      free(http->push_headers);
+      http->push_headers = NULL;
+    }
+  }
+
+  if(!httpc->h2) /* not HTTP/2 ? */
+    return;
+
+  if(premature) {
+    /* RST_STREAM */
+    if(!nghttp2_submit_rst_stream(httpc->h2, NGHTTP2_FLAG_NONE,
+                                  http->stream_id, NGHTTP2_STREAM_CLOSED))
+      (void)nghttp2_session_send(httpc->h2);
+
+    if(http->stream_id == httpc->pause_stream_id) {
+      infof(data, "stopped the pause stream!\n");
+      httpc->pause_stream_id = 0;
+    }
+  }
+
+  if(data->state.drain)
+    drained_transfer(data, httpc);
+
+  /* -1 means unassigned and 0 means cleared */
+  if(http->stream_id > 0) {
+    int rv = nghttp2_session_set_stream_user_data(httpc->h2,
+                                                  http->stream_id, 0);
+    if(rv) {
+      infof(data, "http/2: failed to clear user_data for stream %d!\n",
+            http->stream_id);
+      DEBUGASSERT(0);
+    }
+    http->stream_id = 0;
+  }
+}
+
+/*
+ * Initialize nghttp2 for a Curl connection
+ */
+static CURLcode http2_init(struct connectdata *conn)
+{
+  if(!conn->proto.httpc.h2) {
+    int rc;
+    nghttp2_session_callbacks *callbacks;
+
+    conn->proto.httpc.inbuf = malloc(H2_BUFSIZE);
+    if(conn->proto.httpc.inbuf == NULL)
+      return CURLE_OUT_OF_MEMORY;
+
+    rc = nghttp2_session_callbacks_new(&callbacks);
+
+    if(rc) {
+      failf(conn->data, "Couldn't initialize nghttp2 callbacks!");
+      return CURLE_OUT_OF_MEMORY; /* most likely at least */
+    }
+
+    /* nghttp2_send_callback */
+    nghttp2_session_callbacks_set_send_callback(callbacks, send_callback);
+    /* nghttp2_on_frame_recv_callback */
+    nghttp2_session_callbacks_set_on_frame_recv_callback
+      (callbacks, on_frame_recv);
+    /* nghttp2_on_data_chunk_recv_callback */
+    nghttp2_session_callbacks_set_on_data_chunk_recv_callback
+      (callbacks, on_data_chunk_recv);
+    /* nghttp2_on_stream_close_callback */
+    nghttp2_session_callbacks_set_on_stream_close_callback
+      (callbacks, on_stream_close);
+    /* nghttp2_on_begin_headers_callback */
+    nghttp2_session_callbacks_set_on_begin_headers_callback
+      (callbacks, on_begin_headers);
+    /* nghttp2_on_header_callback */
+    nghttp2_session_callbacks_set_on_header_callback(callbacks, on_header);
+
+#ifndef CURL_DISABLE_VERBOSE_STRINGS
+    nghttp2_session_callbacks_set_error_callback(callbacks, error_callback);
+#endif
+
+    /* The nghttp2 session is not yet setup, do it */
+    rc = nghttp2_session_client_new(&conn->proto.httpc.h2, callbacks, conn);
+
+    nghttp2_session_callbacks_del(callbacks);
+
+    if(rc) {
+      failf(conn->data, "Couldn't initialize nghttp2!");
+      return CURLE_OUT_OF_MEMORY; /* most likely at least */
+    }
+  }
+  return CURLE_OK;
+}
+
+/*
+ * Append headers to ask for a HTTP1.1 to HTTP2 upgrade.
+ */
+CURLcode Curl_http2_request_upgrade(Curl_send_buffer *req,
+                                    struct connectdata *conn)
+{
+  CURLcode result;
+  ssize_t binlen;
+  char *base64;
+  size_t blen;
+  struct SingleRequest *k = &conn->data->req;
+  uint8_t *binsettings = conn->proto.httpc.binsettings;
+  struct http_conn *httpc = &conn->proto.httpc;
+
+  populate_settings(conn, httpc);
+
+  /* this returns number of bytes it wrote */
+  binlen = nghttp2_pack_settings_payload(binsettings, H2_BINSETTINGS_LEN,
+                                         httpc->local_settings,
+                                         httpc->local_settings_num);
+  if(!binlen) {
+    failf(conn->data, "nghttp2 unexpectedly failed on pack_settings_payload");
+    Curl_add_buffer_free(&req);
+    return CURLE_FAILED_INIT;
+  }
+  conn->proto.httpc.binlen = binlen;
+
+  result = Curl_base64url_encode(conn->data, (const char *)binsettings, binlen,
+                                 &base64, &blen);
+  if(result) {
+    Curl_add_buffer_free(&req);
+    return result;
+  }
+
+  result = Curl_add_bufferf(&req,
+                            "Connection: Upgrade, HTTP2-Settings\r\n"
+                            "Upgrade: %s\r\n"
+                            "HTTP2-Settings: %s\r\n",
+                            NGHTTP2_CLEARTEXT_PROTO_VERSION_ID, base64);
+  free(base64);
+
+  k->upgr101 = UPGR101_REQUESTED;
+
+  return result;
+}
+
+/*
+ * Returns nonzero if current HTTP/2 session should be closed.
+ */
+static int should_close_session(struct http_conn *httpc)
+{
+  return httpc->drain_total == 0 && !nghttp2_session_want_read(httpc->h2) &&
+    !nghttp2_session_want_write(httpc->h2);
+}
+
+/*
+ * h2_process_pending_input() processes pending input left in
+ * httpc->inbuf.  Then, call h2_session_send() to send pending data.
+ * This function returns 0 if it succeeds, or -1 and error code will
+ * be assigned to *err.
+ */
+static int h2_process_pending_input(struct connectdata *conn,
+                                    struct http_conn *httpc,
+                                    CURLcode *err)
+{
+  ssize_t nread;
+  char *inbuf;
+  ssize_t rv;
+  struct Curl_easy *data = conn->data;
+
+  nread = httpc->inbuflen - httpc->nread_inbuf;
+  inbuf = httpc->inbuf + httpc->nread_inbuf;
+
+  rv = nghttp2_session_mem_recv(httpc->h2, (const uint8_t *)inbuf, nread);
+  if(rv < 0) {
+    failf(data,
+          "h2_process_pending_input: nghttp2_session_mem_recv() returned "
+          "%zd:%s\n", rv, nghttp2_strerror((int)rv));
+    *err = CURLE_RECV_ERROR;
+    return -1;
+  }
+
+  if(nread == rv) {
+    H2BUGF(infof(data,
+                 "h2_process_pending_input: All data in connection buffer "
+                 "processed\n"));
+    httpc->inbuflen = 0;
+    httpc->nread_inbuf = 0;
+  }
+  else {
+    httpc->nread_inbuf += rv;
+    H2BUGF(infof(data,
+                 "h2_process_pending_input: %zu bytes left in connection "
+                 "buffer\n",
+                 httpc->inbuflen - httpc->nread_inbuf));
+  }
+
+  rv = h2_session_send(data, httpc->h2);
+  if(rv != 0) {
+    *err = CURLE_SEND_ERROR;
+    return -1;
+  }
+
+  if(should_close_session(httpc)) {
+    H2BUGF(infof(data,
+                 "h2_process_pending_input: nothing to do in this session\n"));
+    if(httpc->error_code)
+      *err = CURLE_HTTP2;
+    else {
+      /* not an error per se, but should still close the connection */
+      connclose(conn, "GOAWAY received");
+      *err = CURLE_OK;
+    }
+    return -1;
+  }
+
+  return 0;
+}
+
+/*
+ * Called from transfer.c:done_sending when we stop uploading.
+ */
+CURLcode Curl_http2_done_sending(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+
+  if((conn->handler == &Curl_handler_http2_ssl) ||
+     (conn->handler == &Curl_handler_http2)) {
+    /* make sure this is only attempted for HTTP/2 transfers */
+
+    struct HTTP *stream = conn->data->req.protop;
+
+    if(stream->upload_left) {
+      /* If the stream still thinks there's data left to upload. */
+      struct http_conn *httpc = &conn->proto.httpc;
+      nghttp2_session *h2 = httpc->h2;
+
+      stream->upload_left = 0; /* DONE! */
+
+      /* resume sending here to trigger the callback to get called again so
+         that it can signal EOF to nghttp2 */
+      (void)nghttp2_session_resume_data(h2, stream->stream_id);
+
+      (void)h2_process_pending_input(conn, httpc, &result);
+    }
+  }
+  return result;
+}
+
+static ssize_t http2_handle_stream_close(struct connectdata *conn,
+                                         struct Curl_easy *data,
+                                         struct HTTP *stream, CURLcode *err)
+{
+  char *trailer_pos, *trailer_end;
+  CURLcode result;
+  struct http_conn *httpc = &conn->proto.httpc;
+
+  if(httpc->pause_stream_id == stream->stream_id) {
+    httpc->pause_stream_id = 0;
+  }
+
+  drained_transfer(data, httpc);
+
+  if(httpc->pause_stream_id == 0) {
+    if(h2_process_pending_input(conn, httpc, err) != 0) {
+      return -1;
+    }
+  }
+
+  DEBUGASSERT(data->state.drain == 0);
+
+  /* Reset to FALSE to prevent infinite loop in readwrite_data function. */
+  stream->closed = FALSE;
+  if(httpc->error_code == NGHTTP2_REFUSED_STREAM) {
+    H2BUGF(infof(data, "REFUSED_STREAM (%d), try again on a new connection!\n",
+                 stream->stream_id));
+    connclose(conn, "REFUSED_STREAM"); /* don't use this anymore */
+    data->state.refused_stream = TRUE;
+    *err = CURLE_RECV_ERROR; /* trigger Curl_retry_request() later */
+    return -1;
+  }
+  else if(httpc->error_code != NGHTTP2_NO_ERROR) {
+    failf(data, "HTTP/2 stream %d was not closed cleanly: %s (err %u)",
+          stream->stream_id, http2_strerror(httpc->error_code),
+          httpc->error_code);
+    *err = CURLE_HTTP2_STREAM;
+    return -1;
+  }
+
+  if(!stream->bodystarted) {
+    failf(data, "HTTP/2 stream %d was closed cleanly, but before getting "
+          " all response header fields, treated as error",
+          stream->stream_id);
+    *err = CURLE_HTTP2_STREAM;
+    return -1;
+  }
+
+  if(stream->trailer_recvbuf && stream->trailer_recvbuf->buffer) {
+    trailer_pos = stream->trailer_recvbuf->buffer;
+    trailer_end = trailer_pos + stream->trailer_recvbuf->size_used;
+
+    for(; trailer_pos < trailer_end;) {
+      uint32_t n;
+      memcpy(&n, trailer_pos, sizeof(n));
+      trailer_pos += sizeof(n);
+
+      result = Curl_client_write(conn, CLIENTWRITE_HEADER, trailer_pos, n);
+      if(result) {
+        *err = result;
+        return -1;
+      }
+
+      trailer_pos += n + 1;
+    }
+  }
+
+  stream->close_handled = TRUE;
+
+  H2BUGF(infof(data, "http2_recv returns 0, http2_handle_stream_close\n"));
+  return 0;
+}
+
+/*
+ * h2_pri_spec() fills in the pri_spec struct, used by nghttp2 to send weight
+ * and dependency to the peer. It also stores the updated values in the state
+ * struct.
+ */
+
+static void h2_pri_spec(struct Curl_easy *data,
+                        nghttp2_priority_spec *pri_spec)
+{
+  struct HTTP *depstream = (data->set.stream_depends_on?
+                            data->set.stream_depends_on->req.protop:NULL);
+  int32_t depstream_id = depstream? depstream->stream_id:0;
+  nghttp2_priority_spec_init(pri_spec, depstream_id, data->set.stream_weight,
+                             data->set.stream_depends_e);
+  data->state.stream_weight = data->set.stream_weight;
+  data->state.stream_depends_e = data->set.stream_depends_e;
+  data->state.stream_depends_on = data->set.stream_depends_on;
+}
+
+/*
+ * h2_session_send() checks if there's been an update in the priority /
+ * dependency settings and if so it submits a PRIORITY frame with the updated
+ * info.
+ */
+static int h2_session_send(struct Curl_easy *data,
+                           nghttp2_session *h2)
+{
+  struct HTTP *stream = data->req.protop;
+  if((data->set.stream_weight != data->state.stream_weight) ||
+     (data->set.stream_depends_e != data->state.stream_depends_e) ||
+     (data->set.stream_depends_on != data->state.stream_depends_on) ) {
+    /* send new weight and/or dependency */
+    nghttp2_priority_spec pri_spec;
+    int rv;
+
+    h2_pri_spec(data, &pri_spec);
+
+    H2BUGF(infof(data, "Queuing PRIORITY on stream %u (easy %p)\n",
+                 stream->stream_id, data));
+    rv = nghttp2_submit_priority(h2, NGHTTP2_FLAG_NONE, stream->stream_id,
+                                 &pri_spec);
+    if(rv)
+      return rv;
+  }
+
+  return nghttp2_session_send(h2);
+}
+
+static ssize_t http2_recv(struct connectdata *conn, int sockindex,
+                          char *mem, size_t len, CURLcode *err)
+{
+  CURLcode result = CURLE_OK;
+  ssize_t rv;
+  ssize_t nread;
+  struct http_conn *httpc = &conn->proto.httpc;
+  struct Curl_easy *data = conn->data;
+  struct HTTP *stream = data->req.protop;
+
+  (void)sockindex; /* we always do HTTP2 on sockindex 0 */
+
+  if(should_close_session(httpc)) {
+    H2BUGF(infof(data,
+                 "http2_recv: nothing to do in this session\n"));
+    if(conn->bits.close) {
+      /* already marked for closure, return OK and we're done */
+      *err = CURLE_OK;
+      return 0;
+    }
+    *err = CURLE_HTTP2;
+    return -1;
+  }
+
+  /* Nullify here because we call nghttp2_session_send() and they
+     might refer to the old buffer. */
+  stream->upload_mem = NULL;
+  stream->upload_len = 0;
+
+  /*
+   * At this point 'stream' is just in the Curl_easy the connection
+   * identifies as its owner at this time.
+   */
+
+  if(stream->bodystarted &&
+     stream->nread_header_recvbuf < stream->header_recvbuf->size_used) {
+    /* If there is body data pending for this stream to return, do that */
+    size_t left =
+      stream->header_recvbuf->size_used - stream->nread_header_recvbuf;
+    size_t ncopy = CURLMIN(len, left);
+    memcpy(mem, stream->header_recvbuf->buffer + stream->nread_header_recvbuf,
+           ncopy);
+    stream->nread_header_recvbuf += ncopy;
+
+    H2BUGF(infof(data, "http2_recv: Got %d bytes from header_recvbuf\n",
+                 (int)ncopy));
+    return ncopy;
+  }
+
+  H2BUGF(infof(data, "http2_recv: easy %p (stream %u)\n",
+               data, stream->stream_id));
+
+  if((data->state.drain) && stream->memlen) {
+    H2BUGF(infof(data, "http2_recv: DRAIN %zu bytes stream %u!! (%p => %p)\n",
+                 stream->memlen, stream->stream_id,
+                 stream->mem, mem));
+    if(mem != stream->mem) {
+      /* if we didn't get the same buffer this time, we must move the data to
+         the beginning */
+      memmove(mem, stream->mem, stream->memlen);
+      stream->len = len - stream->memlen;
+      stream->mem = mem;
+    }
+    if(httpc->pause_stream_id == stream->stream_id && !stream->pausedata) {
+      /* We have paused nghttp2, but we have no pause data (see
+         on_data_chunk_recv). */
+      httpc->pause_stream_id = 0;
+      if(h2_process_pending_input(conn, httpc, &result) != 0) {
+        *err = result;
+        return -1;
+      }
+    }
+  }
+  else if(stream->pausedata) {
+    DEBUGASSERT(httpc->pause_stream_id == stream->stream_id);
+    nread = CURLMIN(len, stream->pauselen);
+    memcpy(mem, stream->pausedata, nread);
+
+    stream->pausedata += nread;
+    stream->pauselen -= nread;
+
+    infof(data, "%zd data bytes written\n", nread);
+    if(stream->pauselen == 0) {
+      H2BUGF(infof(data, "Unpaused by stream %u\n", stream->stream_id));
+      DEBUGASSERT(httpc->pause_stream_id == stream->stream_id);
+      httpc->pause_stream_id = 0;
+
+      stream->pausedata = NULL;
+      stream->pauselen = 0;
+
+      /* When NGHTTP2_ERR_PAUSE is returned from
+         data_source_read_callback, we might not process DATA frame
+         fully.  Calling nghttp2_session_mem_recv() again will
+         continue to process DATA frame, but if there is no incoming
+         frames, then we have to call it again with 0-length data.
+         Without this, on_stream_close callback will not be called,
+         and stream could be hanged. */
+      if(h2_process_pending_input(conn, httpc, &result) != 0) {
+        *err = result;
+        return -1;
+      }
+    }
+    H2BUGF(infof(data, "http2_recv: returns unpaused %zd bytes on stream %u\n",
+                 nread, stream->stream_id));
+    return nread;
+  }
+  else if(httpc->pause_stream_id) {
+    /* If a stream paused nghttp2_session_mem_recv previously, and has
+       not processed all data, it still refers to the buffer in
+       nghttp2_session.  If we call nghttp2_session_mem_recv(), we may
+       overwrite that buffer.  To avoid that situation, just return
+       here with CURLE_AGAIN.  This could be busy loop since data in
+       socket is not read.  But it seems that usually streams are
+       notified with its drain property, and socket is read again
+       quickly. */
+    H2BUGF(infof(data, "stream %x is paused, pause id: %x\n",
+                 stream->stream_id, httpc->pause_stream_id));
+    *err = CURLE_AGAIN;
+    return -1;
+  }
+  else {
+    char *inbuf;
+    /* remember where to store incoming data for this stream and how big the
+       buffer is */
+    stream->mem = mem;
+    stream->len = len;
+    stream->memlen = 0;
+
+    if(httpc->inbuflen == 0) {
+      nread = ((Curl_recv *)httpc->recv_underlying)(
+          conn, FIRSTSOCKET, httpc->inbuf, H2_BUFSIZE, &result);
+
+      if(nread == -1) {
+        if(result != CURLE_AGAIN)
+          failf(data, "Failed receiving HTTP2 data");
+        else if(stream->closed)
+          /* received when the stream was already closed! */
+          return http2_handle_stream_close(conn, data, stream, err);
+
+        *err = result;
+        return -1;
+      }
+
+      if(nread == 0) {
+        H2BUGF(infof(data, "end of stream\n"));
+        *err = CURLE_OK;
+        return 0;
+      }
+
+      H2BUGF(infof(data, "nread=%zd\n", nread));
+
+      httpc->inbuflen = nread;
+      inbuf = httpc->inbuf;
+    }
+    else {
+      nread = httpc->inbuflen - httpc->nread_inbuf;
+      inbuf = httpc->inbuf + httpc->nread_inbuf;
+
+      H2BUGF(infof(data, "Use data left in connection buffer, nread=%zd\n",
+                   nread));
+    }
+    rv = nghttp2_session_mem_recv(httpc->h2, (const uint8_t *)inbuf, nread);
+
+    if(nghttp2_is_fatal((int)rv)) {
+      failf(data, "nghttp2_session_mem_recv() returned %zd:%s\n",
+            rv, nghttp2_strerror((int)rv));
+      *err = CURLE_RECV_ERROR;
+      return -1;
+    }
+    H2BUGF(infof(data, "nghttp2_session_mem_recv() returns %zd\n", rv));
+    if(nread == rv) {
+      H2BUGF(infof(data, "All data in connection buffer processed\n"));
+      httpc->inbuflen = 0;
+      httpc->nread_inbuf = 0;
+    }
+    else {
+      httpc->nread_inbuf += rv;
+      H2BUGF(infof(data, "%zu bytes left in connection buffer\n",
+                   httpc->inbuflen - httpc->nread_inbuf));
+    }
+    /* Always send pending frames in nghttp2 session, because
+       nghttp2_session_mem_recv() may queue new frame */
+    rv = h2_session_send(data, httpc->h2);
+    if(rv != 0) {
+      *err = CURLE_SEND_ERROR;
+      return -1;
+    }
+
+    if(should_close_session(httpc)) {
+      H2BUGF(infof(data, "http2_recv: nothing to do in this session\n"));
+      *err = CURLE_HTTP2;
+      return -1;
+    }
+  }
+  if(stream->memlen) {
+    ssize_t retlen = stream->memlen;
+    H2BUGF(infof(data, "http2_recv: returns %zd for stream %u\n",
+                 retlen, stream->stream_id));
+    stream->memlen = 0;
+
+    if(httpc->pause_stream_id == stream->stream_id) {
+      /* data for this stream is returned now, but this stream caused a pause
+         already so we need it called again asap */
+      H2BUGF(infof(data, "Data returned for PAUSED stream %u\n",
+                   stream->stream_id));
+    }
+    else if(!stream->closed) {
+      drained_transfer(data, httpc);
+    }
+    else
+      /* this stream is closed, trigger a another read ASAP to detect that */
+      Curl_expire(data, 0, EXPIRE_RUN_NOW);
+
+    return retlen;
+  }
+  /* If this stream is closed, return 0 to signal the http routine to close
+     the connection */
+  if(stream->closed)
+    return 0;
+  *err = CURLE_AGAIN;
+  H2BUGF(infof(data, "http2_recv returns AGAIN for stream %u\n",
+               stream->stream_id));
+  return -1;
+}
+
+/* Index where :authority header field will appear in request header
+   field list. */
+#define AUTHORITY_DST_IDX 3
+
+#define HEADER_OVERFLOW(x) \
+  (x.namelen > (uint16_t)-1 || x.valuelen > (uint16_t)-1 - x.namelen)
+
+/*
+ * Check header memory for the token "trailers".
+ * Parse the tokens as separated by comma and surrounded by whitespace.
+ * Returns TRUE if found or FALSE if not.
+ */
+static bool contains_trailers(const char *p, size_t len)
+{
+  const char *end = p + len;
+  for(;;) {
+    for(; p != end && (*p == ' ' || *p == '\t'); ++p)
+      ;
+    if(p == end || (size_t)(end - p) < sizeof("trailers") - 1)
+      return FALSE;
+    if(strncasecompare("trailers", p, sizeof("trailers") - 1)) {
+      p += sizeof("trailers") - 1;
+      for(; p != end && (*p == ' ' || *p == '\t'); ++p)
+        ;
+      if(p == end || *p == ',')
+        return TRUE;
+    }
+    /* skip to next token */
+    for(; p != end && *p != ','; ++p)
+      ;
+    if(p == end)
+      return FALSE;
+    ++p;
+  }
+}
+
+typedef enum {
+  /* Send header to server */
+  HEADERINST_FORWARD,
+  /* Don't send header to server */
+  HEADERINST_IGNORE,
+  /* Discard header, and replace it with "te: trailers" */
+  HEADERINST_TE_TRAILERS
+} header_instruction;
+
+/* Decides how to treat given header field. */
+static header_instruction inspect_header(const char *name, size_t namelen,
+                                         const char *value, size_t valuelen) {
+  switch(namelen) {
+  case 2:
+    if(!strncasecompare("te", name, namelen))
+      return HEADERINST_FORWARD;
+
+    return contains_trailers(value, valuelen) ?
+           HEADERINST_TE_TRAILERS : HEADERINST_IGNORE;
+  case 7:
+    return strncasecompare("upgrade", name, namelen) ?
+           HEADERINST_IGNORE : HEADERINST_FORWARD;
+  case 10:
+    return (strncasecompare("connection", name, namelen) ||
+            strncasecompare("keep-alive", name, namelen)) ?
+           HEADERINST_IGNORE : HEADERINST_FORWARD;
+  case 16:
+    return strncasecompare("proxy-connection", name, namelen) ?
+           HEADERINST_IGNORE : HEADERINST_FORWARD;
+  case 17:
+    return strncasecompare("transfer-encoding", name, namelen) ?
+           HEADERINST_IGNORE : HEADERINST_FORWARD;
+  default:
+    return HEADERINST_FORWARD;
+  }
+}
+
+static ssize_t http2_send(struct connectdata *conn, int sockindex,
+                          const void *mem, size_t len, CURLcode *err)
+{
+  /*
+   * Currently, we send request in this function, but this function is also
+   * used to send request body. It would be nice to add dedicated function for
+   * request.
+   */
+  int rv;
+  struct http_conn *httpc = &conn->proto.httpc;
+  struct HTTP *stream = conn->data->req.protop;
+  nghttp2_nv *nva = NULL;
+  size_t nheader;
+  size_t i;
+  size_t authority_idx;
+  char *hdbuf = (char *)mem;
+  char *end, *line_end;
+  nghttp2_data_provider data_prd;
+  int32_t stream_id;
+  nghttp2_session *h2 = httpc->h2;
+  nghttp2_priority_spec pri_spec;
+
+  (void)sockindex;
+
+  H2BUGF(infof(conn->data, "http2_send len=%zu\n", len));
+
+  if(stream->stream_id != -1) {
+    if(stream->close_handled) {
+      infof(conn->data, "stream %d closed\n", stream->stream_id);
+      *err = CURLE_HTTP2_STREAM;
+      return -1;
+    }
+    else if(stream->closed) {
+      return http2_handle_stream_close(conn, conn->data, stream, err);
+    }
+    /* If stream_id != -1, we have dispatched request HEADERS, and now
+       are going to send or sending request body in DATA frame */
+    stream->upload_mem = mem;
+    stream->upload_len = len;
+    rv = nghttp2_session_resume_data(h2, stream->stream_id);
+    if(nghttp2_is_fatal(rv)) {
+      *err = CURLE_SEND_ERROR;
+      return -1;
+    }
+    rv = h2_session_send(conn->data, h2);
+    if(nghttp2_is_fatal(rv)) {
+      *err = CURLE_SEND_ERROR;
+      return -1;
+    }
+    len -= stream->upload_len;
+
+    /* Nullify here because we call nghttp2_session_send() and they
+       might refer to the old buffer. */
+    stream->upload_mem = NULL;
+    stream->upload_len = 0;
+
+    if(should_close_session(httpc)) {
+      H2BUGF(infof(conn->data, "http2_send: nothing to do in this session\n"));
+      *err = CURLE_HTTP2;
+      return -1;
+    }
+
+    if(stream->upload_left) {
+      /* we are sure that we have more data to send here.  Calling the
+         following API will make nghttp2_session_want_write() return
+         nonzero if remote window allows it, which then libcurl checks
+         socket is writable or not.  See http2_perform_getsock(). */
+      nghttp2_session_resume_data(h2, stream->stream_id);
+    }
+
+    H2BUGF(infof(conn->data, "http2_send returns %zu for stream %u\n", len,
+                 stream->stream_id));
+    return len;
+  }
+
+  /* Calculate number of headers contained in [mem, mem + len) */
+  /* Here, we assume the curl http code generate *correct* HTTP header
+     field block */
+  nheader = 0;
+  for(i = 1; i < len; ++i) {
+    if(hdbuf[i] == '\n' && hdbuf[i - 1] == '\r') {
+      ++nheader;
+      ++i;
+    }
+  }
+  if(nheader < 2)
+    goto fail;
+
+  /* We counted additional 2 \r\n in the first and last line. We need 3
+     new headers: :method, :path and :scheme. Therefore we need one
+     more space. */
+  nheader += 1;
+  nva = malloc(sizeof(nghttp2_nv) * nheader);
+  if(nva == NULL) {
+    *err = CURLE_OUT_OF_MEMORY;
+    return -1;
+  }
+
+  /* Extract :method, :path from request line
+     We do line endings with CRLF so checking for CR is enough */
+  line_end = memchr(hdbuf, '\r', len);
+  if(!line_end)
+    goto fail;
+
+  /* Method does not contain spaces */
+  end = memchr(hdbuf, ' ', line_end - hdbuf);
+  if(!end || end == hdbuf)
+    goto fail;
+  nva[0].name = (unsigned char *)":method";
+  nva[0].namelen = strlen((char *)nva[0].name);
+  nva[0].value = (unsigned char *)hdbuf;
+  nva[0].valuelen = (size_t)(end - hdbuf);
+  nva[0].flags = NGHTTP2_NV_FLAG_NONE;
+  if(HEADER_OVERFLOW(nva[0])) {
+    failf(conn->data, "Failed sending HTTP request: Header overflow");
+    goto fail;
+  }
+
+  hdbuf = end + 1;
+
+  /* Path may contain spaces so scan backwards */
+  end = NULL;
+  for(i = (size_t)(line_end - hdbuf); i; --i) {
+    if(hdbuf[i - 1] == ' ') {
+      end = &hdbuf[i - 1];
+      break;
+    }
+  }
+  if(!end || end == hdbuf)
+    goto fail;
+  nva[1].name = (unsigned char *)":path";
+  nva[1].namelen = strlen((char *)nva[1].name);
+  nva[1].value = (unsigned char *)hdbuf;
+  nva[1].valuelen = (size_t)(end - hdbuf);
+  nva[1].flags = NGHTTP2_NV_FLAG_NONE;
+  if(HEADER_OVERFLOW(nva[1])) {
+    failf(conn->data, "Failed sending HTTP request: Header overflow");
+    goto fail;
+  }
+
+  nva[2].name = (unsigned char *)":scheme";
+  nva[2].namelen = strlen((char *)nva[2].name);
+  if(conn->handler->flags & PROTOPT_SSL)
+    nva[2].value = (unsigned char *)"https";
+  else
+    nva[2].value = (unsigned char *)"http";
+  nva[2].valuelen = strlen((char *)nva[2].value);
+  nva[2].flags = NGHTTP2_NV_FLAG_NONE;
+  if(HEADER_OVERFLOW(nva[2])) {
+    failf(conn->data, "Failed sending HTTP request: Header overflow");
+    goto fail;
+  }
+
+  authority_idx = 0;
+  i = 3;
+  while(i < nheader) {
+    size_t hlen;
+
+    hdbuf = line_end + 2;
+
+    /* check for next CR, but only within the piece of data left in the given
+       buffer */
+    line_end = memchr(hdbuf, '\r', len - (hdbuf - (char *)mem));
+    if(!line_end || (line_end == hdbuf))
+      goto fail;
+
+    /* header continuation lines are not supported */
+    if(*hdbuf == ' ' || *hdbuf == '\t')
+      goto fail;
+
+    for(end = hdbuf; end < line_end && *end != ':'; ++end)
+      ;
+    if(end == hdbuf || end == line_end)
+      goto fail;
+    hlen = end - hdbuf;
+
+    if(hlen == 4 && strncasecompare("host", hdbuf, 4)) {
+      authority_idx = i;
+      nva[i].name = (unsigned char *)":authority";
+      nva[i].namelen = strlen((char *)nva[i].name);
+    }
+    else {
+      nva[i].name = (unsigned char *)hdbuf;
+      nva[i].namelen = (size_t)(end - hdbuf);
+    }
+    hdbuf = end + 1;
+    while(*hdbuf == ' ' || *hdbuf == '\t')
+      ++hdbuf;
+    end = line_end;
+
+    switch(inspect_header((const char *)nva[i].name, nva[i].namelen, hdbuf,
+                          end - hdbuf)) {
+    case HEADERINST_IGNORE:
+      /* skip header fields prohibited by HTTP/2 specification. */
+      --nheader;
+      continue;
+    case HEADERINST_TE_TRAILERS:
+      nva[i].value = (uint8_t*)"trailers";
+      nva[i].valuelen = sizeof("trailers") - 1;
+      break;
+    default:
+      nva[i].value = (unsigned char *)hdbuf;
+      nva[i].valuelen = (size_t)(end - hdbuf);
+    }
+
+    nva[i].flags = NGHTTP2_NV_FLAG_NONE;
+    if(HEADER_OVERFLOW(nva[i])) {
+      failf(conn->data, "Failed sending HTTP request: Header overflow");
+      goto fail;
+    }
+    ++i;
+  }
+
+  /* :authority must come before non-pseudo header fields */
+  if(authority_idx != 0 && authority_idx != AUTHORITY_DST_IDX) {
+    nghttp2_nv authority = nva[authority_idx];
+    for(i = authority_idx; i > AUTHORITY_DST_IDX; --i) {
+      nva[i] = nva[i - 1];
+    }
+    nva[i] = authority;
+  }
+
+  /* Warn stream may be rejected if cumulative length of headers is too large.
+     It appears nghttp2 will not send a header frame larger than 64KB. */
+#define MAX_ACC 60000  /* <64KB to account for some overhead */
+  {
+    size_t acc = 0;
+
+    for(i = 0; i < nheader; ++i) {
+      acc += nva[i].namelen + nva[i].valuelen;
+
+      H2BUGF(infof(conn->data, "h2 header: %.*s:%.*s\n",
+                   nva[i].namelen, nva[i].name,
+                   nva[i].valuelen, nva[i].value));
+    }
+
+    if(acc > MAX_ACC) {
+      infof(conn->data, "http2_send: Warning: The cumulative length of all "
+            "headers exceeds %zu bytes and that could cause the "
+            "stream to be rejected.\n", MAX_ACC);
+    }
+  }
+
+  h2_pri_spec(conn->data, &pri_spec);
+
+  switch(conn->data->set.httpreq) {
+  case HTTPREQ_POST:
+  case HTTPREQ_POST_FORM:
+  case HTTPREQ_POST_MIME:
+  case HTTPREQ_PUT:
+    if(conn->data->state.infilesize != -1)
+      stream->upload_left = conn->data->state.infilesize;
+    else
+      /* data sending without specifying the data amount up front */
+      stream->upload_left = -1; /* unknown, but not zero */
+
+    data_prd.read_callback = data_source_read_callback;
+    data_prd.source.ptr = NULL;
+    stream_id = nghttp2_submit_request(h2, &pri_spec, nva, nheader,
+                                       &data_prd, conn->data);
+    break;
+  default:
+    stream_id = nghttp2_submit_request(h2, &pri_spec, nva, nheader,
+                                       NULL, conn->data);
+  }
+
+  Curl_safefree(nva);
+
+  if(stream_id < 0) {
+    H2BUGF(infof(conn->data, "http2_send() send error\n"));
+    *err = CURLE_SEND_ERROR;
+    return -1;
+  }
+
+  infof(conn->data, "Using Stream ID: %x (easy handle %p)\n",
+        stream_id, (void *)conn->data);
+  stream->stream_id = stream_id;
+
+  /* this does not call h2_session_send() since there can not have been any
+   * priority upodate since the nghttp2_submit_request() call above */
+  rv = nghttp2_session_send(h2);
+
+  if(rv != 0) {
+    *err = CURLE_SEND_ERROR;
+    return -1;
+  }
+
+  if(should_close_session(httpc)) {
+    H2BUGF(infof(conn->data, "http2_send: nothing to do in this session\n"));
+    *err = CURLE_HTTP2;
+    return -1;
+  }
+
+  if(stream->stream_id != -1) {
+    /* If whole HEADERS frame was sent off to the underlying socket,
+       the nghttp2 library calls data_source_read_callback. But only
+       it found that no data available, so it deferred the DATA
+       transmission. Which means that nghttp2_session_want_write()
+       returns 0 on http2_perform_getsock(), which results that no
+       writable socket check is performed. To workaround this, we
+       issue nghttp2_session_resume_data() here to bring back DATA
+       transmission from deferred state. */
+    nghttp2_session_resume_data(h2, stream->stream_id);
+  }
+
+  return len;
+
+fail:
+  free(nva);
+  *err = CURLE_SEND_ERROR;
+  return -1;
+}
+
+CURLcode Curl_http2_setup(struct connectdata *conn)
+{
+  CURLcode result;
+  struct http_conn *httpc = &conn->proto.httpc;
+  struct HTTP *stream = conn->data->req.protop;
+
+  stream->stream_id = -1;
+
+  if(!stream->header_recvbuf) {
+    stream->header_recvbuf = Curl_add_buffer_init();
+    if(!stream->header_recvbuf)
+      return CURLE_OUT_OF_MEMORY;
+  }
+
+  if((conn->handler == &Curl_handler_http2_ssl) ||
+     (conn->handler == &Curl_handler_http2))
+    return CURLE_OK; /* already done */
+
+  if(conn->handler->flags & PROTOPT_SSL)
+    conn->handler = &Curl_handler_http2_ssl;
+  else
+    conn->handler = &Curl_handler_http2;
+
+  result = http2_init(conn);
+  if(result) {
+    Curl_add_buffer_free(&stream->header_recvbuf);
+    return result;
+  }
+
+  infof(conn->data, "Using HTTP2, server supports multi-use\n");
+  stream->upload_left = 0;
+  stream->upload_mem = NULL;
+  stream->upload_len = 0;
+
+  httpc->inbuflen = 0;
+  httpc->nread_inbuf = 0;
+
+  httpc->pause_stream_id = 0;
+  httpc->drain_total = 0;
+
+  conn->bits.multiplex = TRUE; /* at least potentially multiplexed */
+  conn->httpversion = 20;
+  conn->bundle->multiuse = BUNDLE_MULTIPLEX;
+
+  infof(conn->data, "Connection state changed (HTTP/2 confirmed)\n");
+  multi_connchanged(conn->data->multi);
+
+  return CURLE_OK;
+}
+
+CURLcode Curl_http2_switched(struct connectdata *conn,
+                             const char *mem, size_t nread)
+{
+  CURLcode result;
+  struct http_conn *httpc = &conn->proto.httpc;
+  int rv;
+  ssize_t nproc;
+  struct Curl_easy *data = conn->data;
+  struct HTTP *stream = conn->data->req.protop;
+
+  result = Curl_http2_setup(conn);
+  if(result)
+    return result;
+
+  httpc->recv_underlying = conn->recv[FIRSTSOCKET];
+  httpc->send_underlying = conn->send[FIRSTSOCKET];
+  conn->recv[FIRSTSOCKET] = http2_recv;
+  conn->send[FIRSTSOCKET] = http2_send;
+
+  if(conn->data->req.upgr101 == UPGR101_RECEIVED) {
+    /* stream 1 is opened implicitly on upgrade */
+    stream->stream_id = 1;
+    /* queue SETTINGS frame (again) */
+    rv = nghttp2_session_upgrade(httpc->h2, httpc->binsettings,
+                                 httpc->binlen, NULL);
+    if(rv != 0) {
+      failf(data, "nghttp2_session_upgrade() failed: %s(%d)",
+            nghttp2_strerror(rv), rv);
+      return CURLE_HTTP2;
+    }
+
+    rv = nghttp2_session_set_stream_user_data(httpc->h2,
+                                              stream->stream_id,
+                                              data);
+    if(rv) {
+      infof(data, "http/2: failed to set user_data for stream %d!\n",
+            stream->stream_id);
+      DEBUGASSERT(0);
+    }
+  }
+  else {
+    populate_settings(conn, httpc);
+
+    /* stream ID is unknown at this point */
+    stream->stream_id = -1;
+    rv = nghttp2_submit_settings(httpc->h2, NGHTTP2_FLAG_NONE,
+                                 httpc->local_settings,
+                                 httpc->local_settings_num);
+    if(rv != 0) {
+      failf(data, "nghttp2_submit_settings() failed: %s(%d)",
+            nghttp2_strerror(rv), rv);
+      return CURLE_HTTP2;
+    }
+  }
+
+#ifdef NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE
+  rv = nghttp2_session_set_local_window_size(httpc->h2, NGHTTP2_FLAG_NONE, 0,
+                                             HTTP2_HUGE_WINDOW_SIZE);
+  if(rv != 0) {
+    failf(data, "nghttp2_session_set_local_window_size() failed: %s(%d)",
+          nghttp2_strerror(rv), rv);
+    return CURLE_HTTP2;
+  }
+#endif
+
+  /* we are going to copy mem to httpc->inbuf.  This is required since
+     mem is part of buffer pointed by stream->mem, and callbacks
+     called by nghttp2_session_mem_recv() will write stream specific
+     data into stream->mem, overwriting data already there. */
+  if(H2_BUFSIZE < nread) {
+    failf(data, "connection buffer size is too small to store data following "
+                "HTTP Upgrade response header: buflen=%zu, datalen=%zu",
+          H2_BUFSIZE, nread);
+    return CURLE_HTTP2;
+  }
+
+  infof(conn->data, "Copying HTTP/2 data in stream buffer to connection buffer"
+                    " after upgrade: len=%zu\n",
+        nread);
+
+  if(nread)
+    memcpy(httpc->inbuf, mem, nread);
+  httpc->inbuflen = nread;
+
+  nproc = nghttp2_session_mem_recv(httpc->h2, (const uint8_t *)httpc->inbuf,
+                                   httpc->inbuflen);
+
+  if(nghttp2_is_fatal((int)nproc)) {
+    failf(data, "nghttp2_session_mem_recv() failed: %s(%d)",
+          nghttp2_strerror((int)nproc), (int)nproc);
+    return CURLE_HTTP2;
+  }
+
+  H2BUGF(infof(data, "nghttp2_session_mem_recv() returns %zd\n", nproc));
+
+  if((ssize_t)nread == nproc) {
+    httpc->inbuflen = 0;
+    httpc->nread_inbuf = 0;
+  }
+  else {
+    httpc->nread_inbuf += nproc;
+  }
+
+  /* Try to send some frames since we may read SETTINGS already. */
+  rv = h2_session_send(data, httpc->h2);
+
+  if(rv != 0) {
+    failf(data, "nghttp2_session_send() failed: %s(%d)",
+          nghttp2_strerror(rv), rv);
+    return CURLE_HTTP2;
+  }
+
+  if(should_close_session(httpc)) {
+    H2BUGF(infof(data,
+                 "nghttp2_session_send(): nothing to do in this session\n"));
+    return CURLE_HTTP2;
+  }
+
+  return CURLE_OK;
+}
+
+CURLcode Curl_http2_add_child(struct Curl_easy *parent,
+                              struct Curl_easy *child,
+                              bool exclusive)
+{
+  if(parent) {
+    struct Curl_http2_dep **tail;
+    struct Curl_http2_dep *dep = calloc(1, sizeof(struct Curl_http2_dep));
+    if(!dep)
+      return CURLE_OUT_OF_MEMORY;
+    dep->data = child;
+
+    if(parent->set.stream_dependents && exclusive) {
+      struct Curl_http2_dep *node = parent->set.stream_dependents;
+      while(node) {
+        node->data->set.stream_depends_on = child;
+        node = node->next;
+      }
+
+      tail = &child->set.stream_dependents;
+      while(*tail)
+        tail = &(*tail)->next;
+
+      DEBUGASSERT(!*tail);
+      *tail = parent->set.stream_dependents;
+      parent->set.stream_dependents = 0;
+    }
+
+    tail = &parent->set.stream_dependents;
+    while(*tail) {
+      (*tail)->data->set.stream_depends_e = FALSE;
+      tail = &(*tail)->next;
+    }
+
+    DEBUGASSERT(!*tail);
+    *tail = dep;
+  }
+
+  child->set.stream_depends_on = parent;
+  child->set.stream_depends_e = exclusive;
+  return CURLE_OK;
+}
+
+void Curl_http2_remove_child(struct Curl_easy *parent, struct Curl_easy *child)
+{
+  struct Curl_http2_dep *last = 0;
+  struct Curl_http2_dep *data = parent->set.stream_dependents;
+  DEBUGASSERT(child->set.stream_depends_on == parent);
+
+  while(data && data->data != child) {
+    last = data;
+    data = data->next;
+  }
+
+  DEBUGASSERT(data);
+
+  if(data) {
+    if(last) {
+      last->next = data->next;
+    }
+    else {
+      parent->set.stream_dependents = data->next;
+    }
+    free(data);
+  }
+
+  child->set.stream_depends_on = 0;
+  child->set.stream_depends_e = FALSE;
+}
+
+void Curl_http2_cleanup_dependencies(struct Curl_easy *data)
+{
+  while(data->set.stream_dependents) {
+    struct Curl_easy *tmp = data->set.stream_dependents->data;
+    Curl_http2_remove_child(data, tmp);
+    if(data->set.stream_depends_on)
+      Curl_http2_add_child(data->set.stream_depends_on, tmp, FALSE);
+  }
+
+  if(data->set.stream_depends_on)
+    Curl_http2_remove_child(data->set.stream_depends_on, data);
+}
+
+/* Only call this function for a transfer that already got a HTTP/2
+   CURLE_HTTP2_STREAM error! */
+bool Curl_h2_http_1_1_error(struct connectdata *conn)
+{
+  struct http_conn *httpc = &conn->proto.httpc;
+  return (httpc->error_code == NGHTTP2_HTTP_1_1_REQUIRED);
+}
+
+#else /* !USE_NGHTTP2 */
+
+/* Satisfy external references even if http2 is not compiled in. */
+#include <curl/curl.h>
+
+char *curl_pushheader_bynum(struct curl_pushheaders *h, size_t num)
+{
+  (void) h;
+  (void) num;
+  return NULL;
+}
+
+char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
+{
+  (void) h;
+  (void) header;
+  return NULL;
+}
+
+#endif /* USE_NGHTTP2 */